This year, more than 4,700 Guatemalan children have been adopted by US families.

This makes Guatemala second only to China as the source of babies adopted by American families - and means one in every 100 Guatemalan children grows up a US citizen.

But that could all be about to change.

Following months of debate, the Guatemalan Congress passed a bill last week bringing national adoption laws into line with an international treaty.

Supporters of the legislation say it will end a murky "baby trade", in which adoption lawyers make big profits and mothers are often paid or coerced to give up their children.

But critics - among them many adoptive parents and lawyers - say it could result in adoptions ending altogether, with the risk that abandoned children end up on the streets.

Fears that 3,700 American families currently seeking to adopt would be stuck in limbo have eased, however, with a provision that their cases can continue under the present rules.

Shadowy figures

Take a closer look at the world of Guatemalan adoptions and it soon becomes clear that there are no easy answers.

At its heart lies poverty, especially among indigenous communities still struggling to recover from a 36-year-long civil war that ended only a decade ago.

About 80% of Guatemala's population of 13 million lives in poverty. At the same time, lack of access to birth control contributes to a high birth rate. Malnutrition is rife.

US families anxious to give a child a better life are ready to pay $30,000 (£15,000) to complete an adoption, of which up to $20,000 goes to lawyers and notaries, in a process largely unregulated by central government.

Adoption supporters argue that many mothers have no choice but to give up a child they cannot feed.

Critics counter with evidence that some lawyers employ "jaladores" - shadowy figures whose task it is to find pregnant women and pay or coerce them to relinquish their child soon after birth - in order to ensure there are babies to offer to adopters.

'Paradise for adoption'

The UN children's agency, Unicef, which estimates that adoptions bring in $100-150m a year to Guatemala, has been among those calling for urgent legal reform.

"This is what the country needs after so many years of being a paradise for adoption," said Manuel Manrique, Unicef's representative in Guatemala.

"[We need] a system where transparency is guaranteed and where the cases of children given in adoption are where the child needs a family, and not what we see now, where families are in need of children."

Mr Manrique believes the fact that a third of the mothers involved in the adoption process give up more than one child supports the claim that they are motivated by financial reward, with $2,000 rumoured to be the going rate.

Norma Cruz, director of Sobrevivientes, said: "We are not against the adoption of children that don't have anyone.

"What we are against is this business that it is has become, where people are getting rich selling kids that have been taken away from their mothers."

'Repulsive'

For the parents adopting from Guatemala - at least 95% of whom come from the US - such claims raise difficult questions about a process in which they have invested time, money and love.

"The thought of a birth mother being paid or coerced or anything like that is repulsive to me," said Katherine O'Meara, from Novi, Michigan, who with husband Brien is adopting twin boys.

"But no matter how much homework you do, I don't know if you can guarantee that you have a 'clean' adoption, where that has not taken place.

"At the same time, I don't believe for a second that that's the main reason why women give up their children. The root of the problem is poverty."

The children Mrs O'Meara is adopting are being cared for at the Casa Quivira children's home in Antigua, the scene of a police raid in August over alleged irregularities. The home's owners denied any wrongdoing.

That raid - and the political row it fuelled - signalled the start of a rollercoaster ride for adoptive parents, desperate not to see the children suffer or cases fall foul of changes in the law.

Until now, Guatemalan adoptions have been popular because they are relatively quick - averaging nine months or so - and because the babies are young, making bonding easier.

DNA 'safeguard'

But that popularity may now wane with Guatemala due to implement the Hague Convention on Inter-Country Adoptions on 31 December. Any cases begun after that date must comply with new requirements.

These include having a central authority to oversee the process, allowing only accredited adoption agencies and imposing a transparent fee system.

The US is itself due to implement the Hague Convention on 1 April.

Last August, the American embassy began requiring a second DNA test to ensure that the baby presented at the start of the process - when the mother is also DNA-tested to ensure she is the child's biological parent - is the same child who receives a visa at the end.

US Ambassador to Guatemala James Derham told the BBC that he believed stories of children being stolen were unlikely to be true, given the requirement for DNA tests and papers signed by the mother.

However, the fact that so many babies come from very poor indigenous communities raises "very real questions about what is the level of consent", he said.

The resulting situation is tough for the embassy, he said, as it seeks to balance the need for adoption reform with helping American adopters.

"They come down here, they fall in love with these children they are going to adopt and also certainly have no interest in buying or coercing the surrender of babies," Ambassador Derham said.

'Mud-slinging'

Among those who have opposed the changes is Guatemalan adoption lawyer Susana Luarca, founder of a children's home and herself the adoptive parent of two children.

"The Hague Convention is not a treaty that helps children," she said. 'It is a treaty that has closed down adoptions in every country where it has been ratified and implemented."

She says many abandoned children will end up in the street because, without the money from adoption fees, privately-run homes that currently take them in will be forced to close.

Ms Luarca says criticism of adoption lawyers' profits is "a mud-slinging campaign" that ignores the expenses involved in feeding, clothing and caring for the adoptive children.

"The best way to kick us out of business would be to offer the same thing. We keep asking officials, why don't they offer the same thing for free, with all the resources the government has?

"We would welcome the competition because that would allow more children to be placed."

Uncertain future

With the new adoption rules due to come into effect soon, the issue of future provision for abandoned children is pressing.

There is only a handful of state-run homes and it is unclear whether the government has the will or the money to set up more.

Nidia Aguilar del Cid, responsible for the rights of the child in the Office of the Human Rights Ombudsman, estimates there are currently 500 privately-run children's homes, of which the government has details of only 300.

While these homes will still be able to operate under the new laws so long as they register, how many will choose to remains to be seen.

"We don't want them to close, we want to regulate them," said Ms Aguilar. "Twenty-thousand children have left the country in the past 10 years - we want to know what happens to them."

Proponents of adoption reform say they do not foresee a flood of abandoned children because most of those in homes now are already promised to adoptive families. They do envisage the "supply" drying up once the financial incentive is gone.

But Congressman Rolando Morales, a driving force behind the reform bill, acknowledges that the authorities have no idea how many children are involved, or what the adoption homes plan to do with those children without a family lined up.

"We don't know if they are going to give them back to their mothers or what they are going to do with them. A lot of awful things may happen," he said.